Fuel tanks have been provided to vehicles with an internal combustion engine as the source of power in order to store the fuel supplying this internal combustion engine. Fuel tanks are formed in shapes suited to the vehicle specific layout; however, the development of so-called saddle-type fuel tanks suited to various types of vehicles such as four-wheel drive cars, rear-wheel drive cars, and hybrid cars has been active in recent years.
Saddle-type fuel tanks have a cross section of a tank bottom along the vehicle width direction that is a concave shape, whereby the two fuel storage portions of a first fuel storage portion and a second fuel storage portion are formed. With such saddle-type fuel tanks, it is necessary to provide a device to keep the liquid level of fuel equal in the two fuel storage portions in order to prevent an excessive amount of fuel from accumulating in either one of the fuel storage portions.
As an example of a fuel tank system equipped with such a device to keep the liquid levels equal, for example, Patent Document 1 shows one provided with a siphon tube that transfers fuel from either one of the first fuel storage portion and the second fuel storage portion to the other.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. H10-61515